klipper Config

Sapphire Pro using BigTreeTech SKR 1.4 & the RPI as a secondary MCU configured with 3d touch see Bltouch offsets & mesh bed levelling sections, please note: Extruder is running in direct drive mode. configured with Klipper, Fluidd & Moonraker

Get USB Id

• ls /dev/serial/by-id/*
• update the printer.cfg with the output, eg: serial:/dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0

Set-up RPI as secondary MCU

• Install the rc script
• cd ~/klipper/
• sudo cp ./scripts/klipper-mcu.service /etc/systemd/system/
• sudo systemctl enable klipper-mcu.service
• Select Linux process
• make menuconfig
• sudo service klipper stop
• make flash
• sudo service klipper start
• sudo usermod -a -G tty pi ** only required if If klippy.log reports a “Permission denied” error

Calibrate Z-offset

• PROBE
• Place a piece of paper under the nozzle
• PROBE_CALIBRATE
• TESTZ Z=-.5 (moves nozzle 0.5 closer to the paper/bed)
• ACCEPT once correct offset
• SAVE_CONFIG will restart the MCU

Section below only applies if using SKR to PI serial UART connection

Using GPIO See vid here for wiring Connect RX , TX & GND pins from TFT header to PI UART GPIO pins 14 & 15 and any Gnd pin ensuring RX & TX are crossed, see here for the PI UART PINOUT. To power the PI from the SKR connect 5v to Pin 2 on the PI

Software Config

• Swapping ports used by GPIO and Bluetooth
• sudo nano /boot/config.txt & append dtoverlay=pi3-miniuart-bt
• Disable the serial console
• sudo nano /boot/cmdline.txt Look for following string (text) and delete console=serial0,115200

Pi serial config

• sudo raspi-config
• select *Interfacing Options*
• *P6 - Serial*
• *No*
• *Yes*
• Exit and reboot.

Rebuild your Klipper MCU firmware

• unselect Use *USB for communication* (instead of serial)
• Flash updated firmware to your board

Update your printer.cfg:

• serial: /dev/ttyAMA0

Related python scripts See here for additional RPI scripts